Examples of the connector of the above described type are disclosed, for example, in the following Patent Literature (PTL) 1 to 3.
FIGS. 7A to 10 show an example of the conventional connector of the above described type. FIG. 7A shows a connector housing 10, FIG. 7B shows a front holder 20, and FIG. 7C shows the front holder 20 in a state fitted to the connector housing 10, respectively in sectional views.
This connector housing 10 is provided with a terminal containing room 11 which has an opening at a backward side, and a terminal 12 equipped with an electric wire (See FIG. 8) is adapted to be inserted into the terminal containing room 11 through this opening. The front holder 20 is inserted and fitted to an engaging front end side of the connector housing 10. The terminal 12 has, at its distal end, a base plate portion 12b to be contacted with a mating terminal (not shown), and a catch portion 12a which is positioned at a back end of the base plate portion 12b and adapted to be locked by a locking lance 13, which will be described below.
The locking lance 13 having flexibility is provided inside the terminal containing room 11 of the connector housing 10, in such a manner that a locking projection 14 of the locking lance 13 projects into the terminal containing room 11 in a free state of the locking lance 13. When the terminal 12 is inserted into the terminal containing room 11, the locking projection 14 of the locking lance 13 is brought into contact with the base plate portion 12b and deflected. Then, the terminal 12 is further inserted into deep, and the locking projection 14 passes the base plate portion 12b to be restored into a not-deflected state. When the locking projection 14 which has been restored into the not-deflected state is engaged with the catch portion 12a of the terminal 12, the terminal 12 is secured in the terminal containing room 11. The state where the locking projection 14 of the locking lance 13 is engaged with the catch portion 12a of the terminal 12 and the locking lance 13 is not deflected, as described above, is called as a completely inserted state of the terminal.
As shown in FIG. 7B, the front holder 20 includes a frame-like part 7 in a shape of a substantially rectangular frame having a front end wall 8, and slides in a direction opposite to an insertion direction of the terminal 12 to be engaged with the connector housing 10. Moreover, a projected part 9 in a shape of a thin plate is formed inside the frame-like part 7 so as to project from the front end wall 8 in a longitudinal direction of the housing. When the front holder 20 is engaged with the connector housing 10 in the completely inserted state of the terminal 12, the projected part 9 is guided by an insertion part 17 in a shape of a hole or groove, and inserted into the connector housing 10. Then, the projected part 9 is inserted into a deflection space 16 which is formed below the locking lance 13 for allowing deflection of the locking lance 13. In case where the terminal 12 is in the completely inserted state, the projected part 9 enters into the deflection space 16 without coming into contact with the locking lance 13, and restricts the deflection of the locking lance 13. In this manner, it is possible to prevent the terminal 12 from being accidentally released from the lock by the locking lance 13 to be withdrawn from the terminal containing room 11.
On the other hand, FIG. 9 shows a state where the locking projection 14 of the locking lance 13 is brought into contact with the base plate portion 12b and deflected, when the terminal 12 is inserted into the terminal containing room 11. Although the state where the locking projection 14 of the locking lance 13 is engaged with the catch portion 12a of the terminal 12 is called as the completely inserted state of the terminal, the state where the locking lance 13 is deflected and the locking projection 14 of the locking lance 13 is not engaged with the terminal 12 is called as an incompletely inserted state of the terminal 12. In the incompletely inserted state of the terminal, the locking lance 13 is deflected toward the deflection space 16 which is formed in the connector housing 10. For this reason, when the front holder 20 is engaged with the connector housing 10 in which the terminal 12 is in the incompletely inserted state, a distal end of the projected part 9 comes into contact with a distal end face of a lance beak part 13a which is positioned at a distal end of the deflected locking lance 13, and relatively thin and long, and the front holder 20 can be no longer pushed in. A worker recognizes that the terminal 12 is in the completely inserted state or in the incompletely inserted state, by sensing whether or not the front holder 20 can be pushed in. When the worker has detected that the terminal is in the incompletely inserted state, the worker pushes the terminal 12 again into the terminal containing room 11 so that the terminal 12 may be brought into the completely inserted state.